Apparatus for forming a blowing pin opening on a parison

ABSTRACT

Movable first and second cutting elements are removably positioned in the pathway of a wall of a parison discharging from a die of an extruder and urged toward the die by biasing means for removing a portion of the wall of the parison at selected locations and forming a parison having an opening through the wall thereof.

I United States Patent 11 1 1111 3,764,249 Powell, Jr. Oct. 9, 1973 [54] APPARATUS FOR FORMING A BLOWING 3,360,827 1/1968 Aichele 425/311 X PIN OPENING ON A PARISON 2,432,734 12/1947 Doesken 425/311 X 2,005,689 6/1935 Hall 425/311 X InventorI William Powell, J a le i e, 3,428,001 2/1969 Zwart, Jr. et a1. 425/311 x Okla. 3,651,725 3/1972 Cook 83/433 X [73] Assignee: Philli ps Petroleum Company,

Bartlesville, Okla. Primary Examiner-J. M. Meister 22 Filed: Sept. 30, 1971 and Quigg [2]] App]. No; 185,256

[57] ABSTRACT [52] Cl 423 5 Movable first and second cutting elements are remov- Cl B26d 3 00 ably positioned in the pathway of a wall of a parison T' 167 discharging from a die of an extruder and urged to- [5 83e Ids; 91:/ 1 ward the die by biasing means for removing a portion of the wall of the parison at selected locations and forming a parison having an opening through the wall [56] References Cited thereofi UNITED STATES PATENTS 598,404 2/1898 Weichert 425/311 12 Claims, 4 Drawing Figures APPARATUS FOR FORMING A BLOWING PIN OPENING ON A PARISON This invention resides in an apparatus and a method for forming an opening in the wall of a parison. In another aspect, this invention resides in an apparatus and a method for continuously forming individual parisons having an opening in a wall of the parison adapted to receive a blow pin.

Blow molding of containers, for example, is accomplished by inserting a blow pin into the end of a parison, closing a mold about the parison, and thereafter blow molding the parison to the configuration of the mold. In some container types, it is desired that the blow pin enter the parison through a side wall of the container for forming a finished blow molded container having only one opening into a chamber of the container with said opening being through the side wall thereof. An example of such a container is a blow molded gasoline tank for vehicles.

I-Ieretofore a single cutting element has been used to form a single slit through a wall of the parison and thereafter insert the blow pin into the parison at an angle of about 90 relative to the center line of the parison. Where a single slit is formed in the parison the after-inserted blow pin often sticks or causes pile up of material which damages the parison and sometimes after blow molding operations the opening is ill formed. These damaged resultant containers must then be discarded which causes waste of materials and labor.

It has been discovered that if the parison extruding from a die is split with spaced apart cutting elements and a portion of the wall between the cutting elements is removed, the resultant parison has an opening which is adapted to receive a blow pin through a side wall thereof without sticking and with the reduction of parison damage. Later it was discovered that if the cutting elements are biased toward the die, that more uniform openings can be formed in the parison.

In summary, the invention resides in first and second cutting elements being removably positioned in the pathway of a wall of a parison discharging from a die of an extruder and being urged toward the die by biasing means for removing a portion of the wall of the parison at selected locations and forming a parison having an opening through the wall thereof.

It is therefore an object of this invention to provide an improved apparatus for forming an opening through a wall of a parison. Another aspect of this invention is to provide an improved apparatus for intermittently removing a portion of a wall of a parison extruded from a die and cutting the extruding parison into desired lengths. Other aspects, objects, and advantages of the present invention will become apparent from a study of the disclosure, the appended claims, and the drawings.

The drawings are diagrammatic views in partial section of the apparatus of this invention and the resultant parison.

FIG. 1 shows the apparatus associated with an extrusion die with cutting elements of the apparatus severing a portion of a wall of the parison from said parison,

FIG. 2 shows a top view of the cutting element,

FIG. 3 shows a resultant individual parison,

FIG. 4 shows another embodiment of the cutting element.

Referring to FIG. 1, a die 2 of an extruder (not shown) is extruding a parison 4 for example. The parison has walls 6 and an end 8. a cutting element 10 has at least first and second spaced apart knife elements 12,14 and is movable relative to the parison 4 by a moving means 16. The moving means 16 is preferably a hydraulic cylinder attached to the knife elements 12,14 for intermittently moving said elements between a first position in which the knife elements 12,14 are laterally spaced from the parison 4 extending from the die 2 and a second position (shown) which the knife elements 12,14 are in the pathway of one wall 6 of the parison discharging from the die for cutting an opening in the parison 4. By so providing a hydraulic moving means 16, the construction of the moving means can be simple and easy to maintain while providing accurate, sensitive controls for the cutting elements 10. The distance at which the first and second knife elements are spaced one from the other is dependent upon the size of blow pin that is to be utilized with the formed parison.

The cutting elements are also provided with means for cutting and removing from the parison the portion 18 of the parison 4 between the first and and second knife elements 12,14. FIG. 2 shows one embodiment of the cutting means which has a third knife element 20 that is attached to and positioned between the first and second knife elements 12,14. In order to provide a cutting surface that will remove the portion 18 of the parison 4 at the end of the cuts made by the first and second knife elements 12,14, it is preferred that the cutting edge of each of the three knife elements 12,14 and 20 be at a common elevation. FIG. 4 shows another embodiment of the cutting element. In this embodiment, the first, second, and third knife elements 12 and 14 are flared outwardly relative to their respective cutting edges 12,14. Element 20 can be vertical. The angle 4) of the downwardly and outwardly flaring of the elements is preferably in the range of about 10 to about 20 relative to the vertical to avoid jamming of the swelling parison material as said material is being cut by the elements. At angles less than about 10 the cut, expanding parison portion often contacts the side walls of the trough and pile up resulting in the malformation of subsequent parisons. At angles greater than about 20 the cut edges of the expanding parison may contact the cutting elements and be deformed.

Referring to FIG. 1, a deflecting plate 22 is angularly attached between the first and second knife elements 12,14 and in the pathway of the portion 18 of the parison 4 between the knife blades in the second position of the knife blades (shown). The deflecting plate 22 contacts the portion 18 being separated from the parison 4 and directs said portion 18 downwardly and outwardly relative to the parison. It is important to keep the parison and portion separated one from the other to avoid adhesion of unwanted material to the parison. The deflecting plate 22 is angularly disposed in a range of about 10 to about 40 relative to the vertical in order to efficiently guide the cut parison portion 18 from the parison 4. At angles greater than about 40 the portion 18 may not be moved smoothly down the deflecting plate 22 but instead may ball, pile, or mound up about the cutting elements which will cause contacting and defective cutting of subsequent parisons. At angles less than about 10 the cut portion is not moved a sufficient distance from the parison without constructing a cutting element having excessive depths thereby representing a waste in construction material and interfering with molds that are positioned below the extrusion parison.

A cutting means 24 such as a severing knife, for example, is provided for cutting in two the parison 4 issuing from the die 2. The cutting means 24 is intermittently operated for cutting the parison issuing from the die at preselected intervals thereby providing separate, individual parisons having a common length. The cutting means 24 can also be used to remove parison material from the die face at other times.

The knife elements 12,14 and 20, at their first position, are preferably laterally positioned from the discharge end 26 of the die 2. At their second position, said elements are in the pathway of the parison when extruded and in contact with the die. By so positioning the knife elements relative to the die and the extruding parison 4 and controlling the movement of the knife elements with the moving means 16, the opening 28 on the wall 6 of the parison 4 formed by the apparatus (better seen in FIG. 3) has its origin at the end 8 of the parison 4 and terminates at a position spaced from said end.

The cutting means 24 is preferably actuated by a hydraulic cylinder 30 as described for the knife elements. The controlling means (not shown) is connected to the moving means 16 and the cylinder 30 for actuating the cutting element 10 and the cutting means 24 at certain preselected intervals that are regulated relative to the rate of discharge of the parison 4 from the die 2.

Referring to FIG. 1, a biasing element 32 is attached to at least one of the cutting elements 10 and the die 2 for urging the cutting element 10 toward a face 36 of the die 2. This is particularly important where the die 2 is a variable orifice die used for example with a programmed extruder. The biasing element 32 can be at least one spring for example for urging the cutting element 10 toward the die face 36 and which permits some vertical movement of the cutting element 10 in response to contact with operating elements of the variable die 2. A hinge or aligning means 34 can be utilized for connecting a hydraulic moving means 16 to the cutting element 10 or the hydraulic moving means 16 to a base frame where it is expected that a mandrel of the variable die 2 will sometimes cause the cutting element to be displaced a relatively large distance from the die face 36. For assuring that the parison is cut by the knife elements as opposed to deforming the parison, the biasing means maintains the knife elements as near the die face 36 as possible.

In the operation of the apparatus of this invention, a parison is intermittently extruded from a die 2 of an extruder. The cutting elements are positioned at their second position in contact with the die and in the pathway of the wall 6 of the parison 4 extruding from the die 2. These cutting elements are moved to the second position and there maintained by the moving means 16 that is attached to said knife or cutting elements. In the second position of the cutting elements, the end 8 of the parison is moved by the extruding parison into contact with the cutting elements and a wall portion of said parison is cut by the continuation of extrusion and movement of the end to lower elevations. At a preselected controlled interval the moving means 16 is actuated which moves the cutting elements to the first position and cuts and removes a portion 18 of the parison 4 from the extruding parison thereby forming a parison with an opening formed through a wall thereof. During extrusion at spaced apart selected intervals, the cylin-.

der 30 moves the cutting means 24 through the parison 4 to sever the parison, form an individual parison having an opening extending therethrough, and initiating a new cycle.

By so constructing an apparatus for cutting the parison discharging from the die and positioning said apparatus in close proximity with the end 26 of the die, the opening 28 can easily be formed in the parison owing to the soft, easily severed condition of the parison at that location.

Other modifications and alterations of this invention will become apparent to those skilled in the art from the foregoing discussion and accompanying drawings, and it should be understood that this invention is not to be unduly limited thereto.

What is claimed is:

1. An apparatus for forming an opening in a parison extruding from a die having a die face, comprising:

at least first and second spaced apart knife elements;

first means for intermittently moving the knife elements between a first position at which the knife elements are laterally spaced from a pathway of a parison extruding from the die and a second position at which the knife elements are in the pathway of only one wall of a parison discharging from the die for cutting an opening in said parison;

second means for urging the knife elements toward the die face; and

third means for cutting and removing from a parison a parison portion between the first and second knife elements.

2. An apparatus, as set forth in claim 1, wherein the means for cutting and removing from the parison the portion of the parison between the first and second knife elements is a third knife element attached to and positioned between the first and second knife elements.

3. An apparatus, as set forth in claim 1, further fourth, means for cutting in two at spaced apart preselected locations a parison extruding from the die.

4. An apparatus, as set forth in claim 1, wherein the first means for moving the knife element between the first and second positions is a hydraulic cylinder.

5. An apparatus, as set forth in claim 1, wherein the lower portion of the first and second knife elements extend downwardly and outwardly from its associated cutting edge at an angle in the range of about 10 to about 20 relative to the vertical.

6. An apparatus, as set forth in claim 1, further including a deflecting plate attached to and extending between the first and second knife elements in the pathway of the portion of the parison between the knife blades in the second position of the knife blades, said deflecting plate extending downwardly and outwardly relative to the vertical in the range of about 10 to about 40 for directing the parison portion outwardly from the parison.

7. An apparatus, as set forth in claim 1, wherein the second means is at least one spring connected to the cutting element and to the die.

8. An apparatus, as set forth in claim 1, including v means for permitting movement of the cutting elements in a direction from a face of the die.

9. An apparatus for forming an opening in a parison extruding from a die having a die face, comprising:

at least first and second spaced-apart knife elements;

first means for intermittently moving the knife elements between a first position at which the knife elements are laterally spaced from a pathway of a parison extruding from the die and a second position at which the knife elements are in the pathway of only one wall of a parison discharging from the die for cutting an opening in the parison;

second means for urging the knife elements toward the die face; and

third means for cutting and removing from a parison a portion between the first and second knife elements, said third means comprising a third knife element attached to and positioned between the first and second knife elements.

10. An apparatus, as set forth in claim 1, wherein the lower portion of the first and second knife elements extends downwardly and outwardly from its associated cutting edge at an angle in the range of about to about 20 relative to the vertical.

11. An apparatus, as set forth in claim 1, further including a deflecting plate attached to and extending between the first and second knife elements in the pathway of the portion of the parison between the knife blades in the second position of the knife blades, said deflecting plate extending downwardly and outwardly relative to the vertical in the range of about 10 to about 40 for directing the parison portion outwardly from the parison.

12. An apparatus, as set forth in claim 11, including a fourth means for cutting in two at spaced-apart preselected locations a parison extruding from the die and wherein the first means is a hydraulic cylinder, the second means is at least one spring connected to the cutting element and to the die, and the lower portion of the first and second knife elements extends downwardly and outwardly from its associated cutting edge at an angle in the range of about 10 to about 20 relative to the vertical.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent Noe 3,761 ,2A9 a October 9, 1973 William D. Powell, Jr;

It is certified that error appears in the above-identified patent and that said letters Patent are hereby corrected as shown below:

Column A, line 31 after "the" insert third lines 35-37, delete "for cutting and removing from the parison the portion of the parison between the first and second knife elements"; line 39, after "further" insert including a line 1 0, after "fourth" delete the comma lines 43-1 delete for moving the knife element between the first and. second positions".

Column 5, line 15, delete "l" and insert 9 line 20, delete "l" and insert 9 Signed and sealed this 16th day of April 197L (SEAL) Attest:

EDX'JARD PLFLETCHERQJR. I C. MARSHALL DANN Attesting Officer Commissioner of Patents 

1. An apparatus for forming an opening in a parison extruding from a die having a die face, comprising: at least first and second spaced apart knife elements; first means for intermittently moving the knife elements between a first position at which the knife elements are laterally spaced from a pathway of a parison extruding from the die and a second position at which the knife elements are in the pathway of only one wall of a parison discharging from the die for cutting an opening in said parison; second means for urging the knife elements toward the die face; and third means for cutting and removing from a parison a parison portion between the first and second knife elements.
 2. An apparatus, as set forth in claim 1, wherein the means for cutting and removing from the parison the portion of the parison between the first and second knife elements is a third knife element attached to and positioned between the first and second knife elements.
 3. An apparatus, as set forth in claim 1, further fourth, means for cutting in two at spaced apart preselected locations a parison extruding from the die.
 4. An apparatus, as set forth in claim 1, wherein the first means for moving the knife element between the first and second positions is a hydraulic cylinder.
 5. An apparatus, as set forth in claim 1, wherein the lower portion of the first and second knife elements extend downwardly and outwardly from its associated cutting edge at an angle in the range of about 10* to about 20* relative to the vertical.
 6. An apparatus, as set forth in claim 1, further including a deflecting plate attached to and extending between the first and second knife elements in the pathway of the portion of the parison between the knife blades in the second position of the knife blades, said deflecting plate extending downwardly and outwardly relative to the vertical in the range of about 10* to about 40* for directing the parison portion outwardly from the parison.
 7. An apparatus, as set forth in claim 1, wherein the second means is at least one spring connected to the cutting element and to the die.
 8. An apparatus, as set forth in claim 1, including means for permitting movement of the cutting elements in a direction from a face of the die.
 9. An apparatus for forming an opening in a parison extruding from a die having a die face, comprising: at least first and second spaced-apart knife elements; first means for intermittently moving the knife elements between a first position at which the knife elements are laterally spaced from a pathway of a parison extruding from the die and a second position at which the knife elements are in the pathway of only one wall of a parison discharging from the die for cutting an opening in the parison; second means for urging the knife elements toward the die face; and third means for cutting and removing from a parison a portion between the first and second knife elements, said third means comprising a third knife element attached to and positioned between the first and second knife elements.
 10. An apparatus, as set forth in claim 1, wherein the lower portion of the first and second knife elements extends downwardly and outwardly from its associated cutting edge at an angle in the range of about 10* to about 20* relative to the vertical.
 11. An apparatus, as set forth in claim 1, further including a deflecting plate attached to and extending between the first and second knife elements in the pathway of the portion of the parison between the knife blades in the second position of the knife blades, said deflecting plate extending downwardly and outwardly relative to the vertical in the rangE of about 10* to about 40* for directing the parison portion outwardly from the parison.
 12. An apparatus, as set forth in claim 11, including a fourth means for cutting in two at spaced-apart preselected locations a parison extruding from the die and wherein the first means is a hydraulic cylinder, the second means is at least one spring connected to the cutting element and to the die, and the lower portion of the first and second knife elements extends downwardly and outwardly from its associated cutting edge at an angle in the range of about 10* to about 20* relative to the vertical. 